Ashtami is the eighth day (Tithi) of Hindu lunar calendar.
Krishna Janmashtami or Gokul Ashtami: is a Hindu festival celebrating the birth of Lord Krishna, an avatar of Hindu deity Vishnu.
Krishna Janmashtami is observed on the Ashtami tithi, the eighth day of the dark half or Krishna Paksha of the month of Bhaadra in the Hindu calendar, when the Rohini Nakshatra (called Aldebaran in the West) is ascendant. Rasa lila or dramatic enactments of the life of Krishna are a special feature in regions of Mathura, and Vrindavan, Nalbari and regions following Vaishnavism in Manipur.